Air cleaning devices comprising a filter with a filter medium of dielectric and/or pre-charged material and ionizing means for charging airborne particles before they hit the filter are proven to be more efficient than air cleaning devices merely utilizing a filter. The particles charged by the ionizing means are attracted by the fibers of the filter by electrostatic force. An example of such an air cleaning device is disclosed in EP 980290 B1. However, in the field of air cleaning, there is a need to further improve the air cleaning efficiency of air cleaning devices.